A novel approach to the deposition of Co-Mo-Cr-Si coating on Haynes 282 by laser fusion and laser remelting

This paper presents a novel hybrid method of the crack -free fusion of CoMoCrSi, which is a cobalt-based alloy with molybdenum additions with the composition analogous to Tribaloy (R) T400, on Haynes 282 for parts where extreme wear is problematic with high temperatures and corrosive media, such as industrial turbine applications, commercial jet engines, and rocket engines. To alleviate cracking of the coating during laser surface deposition/ coating, previous attempts relied on preheating of the substrate to reduce cracks to alleviate a thermal mismatch between the substrate and molten powder. The primary aim of this work is accomplished by fusing crack free CoMoCrSi layers using a novel hybrid process of combining laser cladding and laser remelting processes. The optimal process conditions of coating crack -free CoMoCrSi on Haynes 282 were determined for both the laser powderbed fusion and remelting processes. Microhardness and chemical compositions of the coating layers produced using optimal process parameters with and without remelting the substrate were compared. The chemical compositions of different phases present in the coating layer were analyzed by Energy Dispersive X-ray Spectroscopy (EDS). The remelting process yielded no dilution at the surface, resulting in the preservation of the original CoMoCrSi coating properties.